Voters will nominate candidates in Nebraska and West Virginia today under the watchful eye of national tea party groups and leaders, who have the most at stake. A heated Senate primary in Nebraska is the marquee race, while an intense gubernatorial campaign and a crowded U.S. House contest have also caught the attention of Republicans.

Former Alaska governor Sarah Palin, left, Texas Sen. Ted Cruz, Sharon Lee, Utah Sen. Mike Lee and former Nebraska governor Kay Orr, stand together on the platform at Buffalo Bill State Historical Park Friday, April 25, 2014, in North Platte, Neb., at a rally for Republican U.S. Senate candidate Ben Sasse. (AP Photo/The Telegraph, Job Vigil)

We'll have results for you on Post Politics this evening. In the meantime, here's everything you need to know about the day.

You mentioned the Senate race. Why does it stand out?

Tea party groups and figures have put all their muscle behind Midland University President Ben Sasse in the open race for the seat of retiring Sen. Mike Johanns (R-Neb.). The Club for Growth and Senate Conservatives Fund have spent money for him; Sens. Ted Cruz (R-Tex.) and Mike Lee (R-Utah) have stumped for him; and Sasse's candidacy even prompted the tea party group FreedomWorks to defect from one of his opponents.

Sasse may be the frontrunner, but he's no shoo-in. After an intense battle against establishment favorite and former state treasurer Shane Osborn, which was full of attacks and counterpunches from Sasse's allies and Osborn, wealthy bank executive Sid Dinsdale has been surging and stands a chance of winning. The Republican nominee will almost certainly win the general election, given the state's conservative tilt.

Haven't we seen this movie before?

You could say that, yes. The 2012 primary for U.S. Senate in Nebraska featured a tea party favorite and establishment choice beating each other up for months, clearing the way for now-Sen. Deb Fischer (R) to make a late and unexpected surge. The difference is that Dinsdale hasn't been getting the big-name 11th hour endorsements that signaled Fischer's momentum. So the ending might be different this time.

So why is a Sasse win so important for the tea party?

Because not only did tea partyers go all in for him, they did so in an election cycle that does not present them with many opportunities for victories against establishment-backed Senate candidates. Next week in Kentucky, Senate Minority Leader Mitch McConnell is expected to cruise against businessman Matt Bevin. And neither of the tea party challengers running against Sens. Thad Cochran (R-Miss.) and Pat Roberts (R-Kan.) have made major strides. A handful of other Republican senators face only small-time tea party challengers, despite an early effort to recruit serious contenders to face them. If the tea party doesn't win in Nebraska, it could be in for a long summer.

What about the governor's race?

That's also very interesting. Limited polling on the GOP primary shows Attorney General Jon Bruning in a tight race against Pete Ricketts, head of the Platte Institute for Economic Research. Ricketts is also the son of billionaire TD Ameritrade co-founder Joe Ricketts, a major conservative donor. So it's no surprise that potential 2016 presidential candidates such as Cruz, Wisconsin Gov. Scott Walker, Indiana Gov. Mike Pence and Rep. Paul Ryan (R-Wis.) are backing Ricketts. Bruning got an endorsement late in the race from outgoing Nebraska Gov. Dave Heineman (R).

What should we watch in West Virginia?

The most interesting race is the GOP primary in Rep. Shelley Moore Capito's staunchly Republican district. Capito is running for U.S. Senate, and the crowded battle for her seat has pitted establishment-favored Charlotte Lane, a former head of the U.S. International Trade Commission, against former Maryland Republican Party chairman Alex Mooney and self-funder Ken Reed. (Roll Call has a good rundown of the matchup here.) Tea party groups are backing Mooney, but he has faced carpetbagging charges. The nonpartisan Cook Report has labeled the 2nd District "Lean Republican" even though Mitt Romney won 60 percent of the vote there in 2012. Thanks in part to a messy GOP primary that has allowed attorney Nick Casey (D) to coast, Democrats may be able to contest the seat in November.

What times do polls open and close?

Polls in Nebraska will be open from 9 a.m. to 9 p.m. Eastern time. In West Virginia, they opened at 6:30 a.m Eastern time and close at 7:30 p.m.